Lock for slidable jaw wrench



NOV. 24, 1959 w, RQZMUS 2,913,942

LOCK FOR SLIDABLE JAW WRENCH Filed Feb. 21, 1958 INVENTOR. WALTER J. ROZ MUS ATTORNEYS LOCK FOR SLIDABLE JAW WRENCH Walter J. Rozmus, Whitesboro, N.Y., assignor to Kelsey-Hayes Company Application February 21, 1958, Serial No. 716,790

3 Claims. 01. 81--165) The invention relates in general to adjustable jaw wrenches, such for example, as sliding side jaw wrenches; and relates more specifically to an improved, novel locking mechanism for the sliding jaw of such wrenches;

The primary object of this invention is to provide a worm gear lock of improved operating characteristics for a sliding jaw wrench.

Another object of this invention is to eliminate costly interior locking surfaces employed in conventional sliding worm gear axles. 1

Yet another object of this invention is to provide locking positions for a worm gear, which positions are very closely spaced for small increments of jaw adjustability between lock positions.

Yet another object of this invention is to place full control for a worm gear lock at the natural thumb location of the operator for one-handed operation.

And still another object of this invention is to provide a surface-positioned lock device which cannot be driven away from the worm gear by action of the worm gear.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

Figure l is a plan view of a slidable side jaw adjustable wrench provided with improved features of this invention, the locking mechanism being in the release position;

Figure 2 is a plan view as in Figure 1, with the locking mechanism in the lock position; and,

Figure 3 is a fragmentary section taken along the line 3-3 of Figure 2.

There have been a multitude of proposals for providing a lock device for selectively locking the jaw of sliding jaw wrenches. Many of these suggestions have been patented and are well illustrated in the United States patent references. However, most of these devices require internally formed shapes with operating mechanism to shift a lock member between clutching and releasing positions. Such internal formations are expensive and subject to rapid deterioration. Some exterior lock devices of rather crude form have been proposed. The best of such proposals have inherent weaknesses such as the ability to be easily dislodged from a locking condition unintentionally.

The improved and novel lock device of this invention is easily applied to a standard tool without particular modification of the tool. The preferred field for such lock device is in the sliding side jaw wrench field. Accordingly, the preferred embodiment of this invention is a locking device applied to a sliding side jaw wrench, and the preferred form of the lock device is a twin bladed lock member as shown in the drawing. The sliding side jaw wrench is indicated by the reference character 10. The wrench is of the usual form having a wrench body 11 with a fixed jaw 12 and a sliding side jaw 13. A lateral opening 14 through the body 11 is provided to house a worm gear 16. Rack teeth 15 on the jaw 13 intermesh with the worm gear 16 in the usual manner for ICC a longitudinal adjustment of jaw 13 with respect to jaw 12.

The worm gear 16 is of usual form with a continuous spiral 17. The spiral 17 has an exterior edge which, in effect, defines the exterior surface profile of the worm gear. Contact with one or more adjacent sections of the spiral 17 may be referred to as contact with the sur face of the worm gear. 1

Into this invironment, the improvement of the present invention comprises a lock member 20 for securing any selected jaw position. Thelock member 20 has a worm engaging portion '21 and a driving handle portion 22. The lock member 20' is pivotally carried upon the body 11 of the wrench 10 by means of a pivot 23. Lock mem-' ber 20 is a generally U-shaped member straddling the wrench handle with the free ends of the U.-shaped member provided in a blade formation serving as the worm; engaging portion 21. The bottom portion of the U- shaped member provides the drive handle portion 22 extending beyond the side edge of the wrench body or handle 11 and movable by thumb operation by the operator.

The portion 22 has a range of movement between a first. 'and second limit by reason of its physical form and pivotal mounting. The blade ends forming the worm engaging portion 21 likewise move responsively between first and second limits.

Friction of the device 20 on the surface of the .body 11 is generally suflicient to hold the lock member in the assurance thatthelock will stay in the lock condition until deliberately released. Accordingly, the body 11 is provided with an indent groove surface 26 and the lock member 20 is provided with the surface engagement portion 27 to lock into the groove 26. In the illustrated embodiment of the invention, the surface 27 is a coined indent made from the exterior surface of the lock and thereby provides a bulge on the interior surface. The detent has been located such that it swings generally free of the wrench body 11 after being disengaged from the groove 26. The resilient nature of the saddle formation of the lock 20 provides sufficient resiliency to permit entry of the portion 27 into the groove 26, but permitting forced release from engagement.

The blade ends of the U-shaped member 20 are relatively narrow, as best seen in Figure 3. The surface edge of the spiral 17 is serrated, as is usually the case for such worm gears. Serrations are generally provided for aid in increasing grippability. These serrations are indicated by the reference character 25 in the Figure 3. The blade formation readily interlocks with these serrations 25 to hold the worm gear against retraction and consequently lock the jaw 13 in the particular position where it is required when such engagement is accomplished.

The Worm engaging portion 21 is formed eccentrically with respect to the pivot 23 in order that the blade surfaces will approach the worm gear profile and engage into the serrations 25 upon shifting of the member 20 to the locking position, which may be referred to as the second limit of movement.

From the foregoing description of this preferred embodiment as applied to a sliding side jaw wrench, it will be readily apparent that a very inexpensive construction has been accomplished; but even more important, the construction is expressly free of malfunction. Furthermore, a vastly increased number of locking positions is available by this invention over those employing internal non-circular forms to achieve locking. Such internal forms provide six or eight positions as a practical maxidirected in a lateral direction with respect to the path of movement of the lock device.

It is believed that the exceptionally simplified desirable construction will be readily apparent by observation of the drawing with the description of the invention that has been given.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way'of example and that.

numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. A slidable side jaw wrench comprising a handle member having one end formed to provide a fixed jaw portion, a slidable jaw member, said fixed jaw and slidable jaw portions having interconnected guideways to permit movement of the slidable jaw along a rectilinear path, said slidable jaw having a rack, a worm gear rotatably carried by the handle member and engaged with said rack, a lock member, said lock member having a worm engaging edge, pivot means providing a pivot axis transverse to the axis of rotation of said worm gear, said look member being mounted on said handle member for pivotal movement about said pivot means, said worm engaging edge being eccentric :to said pivot means, said lock member having a handle, said handle having a range of movement between a first and a second limit, said worm engaging edge being movable responsively between said first and second limits, said worm engaging edge at said second limit being interlocked with said worm gear to hold the worm gear against rotation, rotational forces of the worm gear when in locked engagement by said lock member exerting a force upon said lock member in a direction through said pivot means axis, whereby pivotal movement of said lock member by said forces is prevented.

2. In the wrench construction of claim 1, the lock member handle extending laterally beyond the edge of the wrench handle for thumb activation by the operator.

3; In the wrench construction of claim 1 the lock member having a U-shaped body straddling the wrench handle, the free ends of the U each having an eccentric blade edge formation pivotable about the pivot axis, and the bottom portion of the U being a handle extending beyond the edge of the wrench handle for thumb activation by the operator.

References Cited in the file of this patent UNITED STATES PATENTS 1,367,408 McClurkin Feb. 1, 1921 1,599,162 Brown Sept. 7, 1926 1,749,002 Schneider et al. Mar. 4, 1930 2,309,529 Orchard Jan. '26, 1943 2,688,893 Jackson Sept. 14, 1954 2,714,323 Lyons Aug. 2, 1955 2,755,693 Hund July 24, 1956 2,780,124 Lyons Feb. 5, 1957 

